Transforming growth factor (TGF)-β levels and unprovoked recurrent venous thromboembolism

Transforming Growth Factors in Venous Thrombus Formation and Resolution

Deep vein thrombosis (DVT) and pulmonary embolism are vascular occlusive disorders categorized under the term venous thromboembolism. Venous thromboembolism affects ≈900 000 people per year in the United States alone. Understanding of the multifaceted process of DVT has improved in recent years, and current DVT treatments reduce thrombus propagation, but they also increase bleeding risk and fail to accelerate natural venous thrombus resolution. Multiple inflammatory cytokines regulate the development and subsequent resolution of DVT. One family of cytokines involved in DVT and venous thrombus resolution is the TGF-β (transforming growth factor-β) family. A comprehensive understanding of the control of venous thrombus formation and resolution by the TGF-β family could lead to the development of novel treatments for DVT that target ≥1 of the TGF-β isoforms. The aim of this review is to describe studies of the roles of the TGF-β isoforms in venous thrombus formation and resolution and to highlight opportunities for future research. TGF-β isoforms include TGF-β1, TGF-β2, and TGF-β3. TGF-β1 has a well-characterized role in the positive regulation of venous thrombus formation and the negative regulation of venous thrombus resolution. Further research is necessary, however, to understand the potential roles of TGF-β2 and TGF-β3 in venous thrombus formation and resolution. Given that TGF-β1 expression increases during venous thrombosis and that inhibition or knockdown of TGF-β1 reduces thrombus burden, TGF-β1 represents a potential diagnostic marker for DVT and a putative target for therapies that aim to prevent or treat DVT.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

Novel Insight into Inflammatory Pathways in Acute Pulmonary Embolism in Humans

Accumulating data have shown a pathophysiological association between inflammatory pathways and thrombosis. Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and acute pulmonary embolism (APE), is a significant health burden. It involves not only hemodynamic disturbances due to the emboli occluding the pulmonary arteries, but also platelet activation, endothelial dysfunction, and "firing up" of the inflammatory cascade. In humans, the systemic inflammatory state can also be evaluated using plasma levels of C-reactive protein (CRP) and interleukin (IL)-6, which correlate with venous obstruction, thrombus extension, and clinical VTE complications such as postthrombotic syndrome, recurrent thromboembolism, worse quality of life, and functional impairment. The exaggerated inflammatory state during postthrombotic syndrome aligns with severe alterations in endothelial function, such as activation of intercellular adhesion molecule (ICAM)-1 and E-selectin, as well as vascular proteolysis and fibrinolysis. Moreover, a hypercoagulable state, indicated by higher levels of von Willebrand factor (vWF) and factor VIII, is closely associated with the inflammatory response. We aimed to describe the role of basic inflammatory markers in daily clinical practice as well as the most important cytokines (IL-1β, IL-6, IL-8, tumor necrosis factor-a [TNF-α], growth differentiation factor-15 [GDF-15]). These markers could provide valuable insight into the interplay between thrombosis and inflammation, helping inform better management and treatment strategies.

Circulating miR-320a-3p and miR-483-5p level associated with pharmacokinetic-pharmacodynamic profiles of rivaroxaban

BACKGROUND

Novel biomarkers for personalizing anticoagulation remain undetermined. We aimed to investigate the association of plasma miRNAs with pharmacokinetic-pharmacodynamic (PK-PD) profiles of rivaroxaban.

METHODS

This is a multicenter, exploratory study of miRNAs in a Chinese population. Healthy volunteers and patients receiving rivaroxaban were enrolled in the study. The area under the plasma concentration-time curve from time 0-t h (AUC_0-t) and anti-Xa activity at 3 h (AXA_3h) were measured in healthy volunteers, and AXA_3h was measured in patients. MiRNAs were detected by miRNA microarray in 26 healthy volunteers with 20 mg rivaroxaban, and quantitative reverse transcription polymerase chain reaction was used to exclude undetectable ones. MiR-320a-3p and miR-483-5p were then quantified in 65 healthy volunteers and 71 patients. MiRNA levels at 3 h were compared between high and low AXA_3h or AUC_0-t subjects and in matched patients with or without bleeding during follow-up. The miRNA targets were predicted by TargetScan, miRTarBase, and miRDB. Validated genes were included in GO enrichment and KEGG analyses. The protein-protein interaction network was established by STRING and visualized by Cytoscape.

RESULTS

A total of 136 Chinese subjects completed the study. In healthy volunteers taking 15 mg rivaroxaban, the miR-320a level at 3 h was significantly positively correlated with AXA_3h and AUC_0-t (r = 0.359, p = 0.025; r = 0.370, p = 0.02, respectively). A positive correlation was also observed between miR-483 and AXA_3h or AUC_0-t (r = 0.372, p = 0.02; r = 0.523, p = 0.001, respectively). MiR-320a and miR-483 levels at 3 h in the higher AUC_0-t group were significantly higher than those at 0 h. MiR-483 levels at 3 h may distinguish healthy volunteers with high or low AXA_3h or AUC_0-t. In the 10 mg fed subgroup, higher 3 h mir-483 levels were also observed compared with the control group. No significant differences were found in the comparisons among patients. Bioinformatic analysis showed that these miRNAs may play a regulatory role by targeting ABCG2, ITGB3, PTEN, MAPK1/3, etc. CONCLUSIONS: MiR-320a and miR-483 levels were found to be associated with PK and PD profiles of rivaroxaban in healthy Chinese subjects. Further studies are required to verify these findings and explore the mechanisms.

Association of recurrent venous thromboembolism and circulating microRNAs

BACKGROUND

Patients with unprovoked first venous thromboembolism (VTE) are at a high risk of recurrence. Although circulating microRNAs (miRNAs) have been found to be associated with VTE and are markers of hypercoagulability, this study is the first to examine whether circulating miRNAs are associated with the risk of VTE recurrence.

RESULTS

A nested case-control study design was used where plasma samples were obtained from 78 patients with unprovoked VTE from the Malmö Thrombophilia Study (MATS). A total of 39 VTE patients with recurrent VTE (cases) were matched with 39 VTE patients without recurrent VTE (controls) defined by age and sex (MATS population). Plasma levels of 179 different miRNAs were evaluated in the 78 samples (after anticoagulant treatment was stopped) using qPCR. A total of 110 miRNAs were detected in all samples. Among those, 12 miRNAs (miR-15b-5p, miR-106a-5p, miR-197-3p, miR-652-3p, miR-361-5p, miR-222-3p, miR-26b-5p, miR-532-5p, miR-27b-3p, miR-21-5p, miR-103a-3p, and miR-30c-5p) were found to be associated with recurrent VTE after multiple correction test and conditional logistic regression analysis. A further analysis showed that miR-15b-5p, miR-197-3p, miR-27b-3p, and miR-30c-5p exhibited a trend over time, with a larger difference in miRNA levels between cases and controls for earlier recurrence. Of these 12 miRNAs, 8 miRNAs significantly correlated with circulating transforming growth factor β1/2 (TGFβ1/2). Three of them correlated with platelet count.

CONCLUSION

We have identified 12 plasma miRNAs that may have the potential to serve as novel, non-invasive predictive biomarkers for VTE recurrence.

Transforming Growth Factor Beta-1 in Human Breast Milk and Its Correlation with Infants' Parameters

Background: Breastfeeding provides optimal nutrition and health protection for the infant; it contains many anti-inflammatory factors, including transforming growth factor beta-1 (TGF-β1). Our study aimed to measure the level of TGF-β1 in human milk and to find its correlation with some infant anthropometric characteristics. Subjects and Methods: A milk sample was collected from 84 mothers and the level of TGF-β1 was measured using enzyme-linked immunosorbent assay. Results: TGF-β1 was significantly higher in vegetarian mothers compared with nonvegetarian mothers (p = 0.044). Additionally, the mean value of breast milk TGF-β1 was significantly higher in mothers using contraceptive pills compared with those who do not (p = 0.021). Also, the mean value of TGF-β1 was significantly higher in infants 3-6 months than those <3 months (p = 0.010); also there was a significant difference regarding infants' weight and length with average weight and length (p = 0.042) and (p = 0.009), respectively. Conclusions: TGF-β1 in human milk may play a role in infants' growth and development; mothers' diet is known to influence TGF-β1 level and its relation to infants' age and weight. Contraceptive method could have an influence on TGF-β1 levels during breastfeeding.

Cytokines, Adhesion Molecules, and Matrix Metalloproteases as Predisposing, Diagnostic, and Prognostic Factors in Venous Thrombosis

The inflammatory response is a well-established part of, and a prerequisite for, venous thrombosis. To better understand the pathophysiology of venous thrombosis and to identify improved diagnostic biomarkers, further studies of the relationship between inflammation and coagulation are needed. We review previous studies concerning inflammatory biomarkers in venous thromboembolism, in particular cytokines, soluble adhesion molecules and matrix metalloproteases as predisposing, diagnostic and prognostic factors in venous thrombosis. Elevated cytokines and genetic alterations coding for cytokines are found in several patient cohorts which indicate that cytokines are involved as predisposing factors in venous thrombosis development. Increased levels of pro-inflammatory cytokines are detected both in animal models and in patients with acute venous thrombosis and clinical trials, although currently without evident diagnostic value. Adhesion molecules are crucial in the development of venous thrombosis, especially P-selectin seems important in initiating leukocyte accumulation and adhesion to endothelium for subsequent platelet accumulation. Several studies have demonstrated increased soluble P-selectin levels in patients with venous thrombosis, emphasizing its potential role as diagnostic marker and also as a therapeutic target. Matrix metalloproteases are essential effectors during venous thrombosis resolution and may impact vessel wall fibrosis, and together with their natural occurring inhibitors are crucial in acute and chronic thrombosis pathophysiology. Furthermore, studies in animal models of venous thrombosis have demonstrated anti-inflammatory treatment to be effective in terms of thrombus resolution and reduction of vessel wall damage, without increase in bleeding risk during the course of treatment. Thus, soluble mediators should be further investigated both as possible biomarkers and therapeutic targets in venous thromboembolic disease.

Identification of unique venous thromboembolism-susceptibility variants in African-Americans

To identify novel single nucleotide polymorphisms (SNPs) associated with venous thromboembolism (VTE) in African-Americans (AAs), we performed a genome-wide association study (GWAS) of VTE in AAs using the Electronic Medical Records and Genomics (eMERGE) Network, comprised of seven sites each with DNA biobanks (total ~39,200 unique DNA samples) with genome-wide SNP data (imputed to 1000 Genomes Project cosmopolitan reference panel) and linked to electronic health records (EHRs). Using a validated EHR-driven phenotype extraction algorithm, we identified VTE cases and controls and tested for an association between each SNP and VTE using unconditional logistic regression, adjusted for age, sex, stroke, site-platform combination and sickle cell risk genotype. Among 393 AA VTE cases and 4,941 AA controls, three intragenic SNPs reached genome-wide significance: LEMD3 rs138916004 (OR=3.2; p=1.3E-08), LY86 rs3804476 (OR=1.8; p=2E-08) and LOC100130298 rs142143628 (OR=4.5; p=4.4E-08); all three SNPs validated using internal cross-validation, parametric bootstrap and meta-analysis methods. LEMD3 rs138916004 and LOC100130298 rs142143628 are only present in Africans (1000G data). LEMD3 showed a significant differential expression in both NCBI Gene Expression Omnibus (GEO) and the Mayo Clinic gene expression data, LOC100130298 showed a significant differential expression only in the GEO expression data, and LY86 showed a significant differential expression only in the Mayo expression data. LEMD3 encodes for an antagonist of TGF-β-induced cell proliferation arrest. LY86 encodes for MD-1 which down-regulates the pro-inflammatory response to lipopolysaccharide; LY86 variation was previously associated with VTE in white women; LOC100130298 is a non-coding RNA gene with unknown regulatory activity in gene expression and epigenetics.

Platelet-rich plasma stimulates human dermal fibroblast proliferation via a Ras-dependent extracellular signal-regulated kinase 1/2 pathway

Platelet-rich plasma (PRP) contains a high concentration of several growth factors and contributes to soft-tissue engineering and wound healing. However, the effect of PRP on human dermal fibroblast proliferation and responses is unknown. This was investigated in the present study using PRP prepared from the whole human blood using the double-spin method. Human dermal fibroblast cultures were established from skin samples collected during plastic surgery. Platelet concentration and growth factor levels in PRP were estimated, and a cell proliferation assay was carried out after PRP treatment. The role of Ras-dependent extracellular signal-regulated kinase (ERK)1/2 in the effects of PRP was investigated in human dermal fibroblasts by suppressing ERK1/2 expression with an inhibitor or by short interfering (si)RNA-mediated knockdown, and assessing ERK1/2 phosphorylation by western blotting as well as proliferation in PRP-treated cells. We found that PRP stimulated human dermal fibroblast proliferation, which was suppressed by ERK1/2 inhibitor treatment (P < 0.01). ERK1/2 phosphorylation was increased in the presence of PRP, while siRNA-mediated knockdown of ERK1/2 blocked cell proliferation normally induced by PRP treatment (P < 0.01). These results demonstrate that PRP induces human dermal fibroblast proliferation via activation of ERK1/2 signaling. Our findings provide a basis for the development of agents that can promote wound healing and can be applied to soft-tissue engineering.

Plasminogen activator inhibitor-1 4G/5G polymorphism, factor V Leiden, prothrombin mutations and the risk of VTE recurrence

Plasminogen-activator inhibitor (PAI)-1 is an important inhibitor of the plasminogen/plasmin system. PAI-1 levels are influenced by the 4G/5G polymorphism in the PAI-1 promoter. We investigated the relationship between the PAI-1 polymorphism and VTE recurrence, and its possible modification by factor V Leiden (FVL) and prothrombin (PTM) mutations. Patients (n=1,069) from the Malmö Thrombophilia Study were followed from discontinuation of anticoagulant treatment until diagnosis of VTE recurrence or the end of the study (maximum follow-up 9.8 years). One hundred twenty-seven patients (11.9 %) had VTE recurrence. PAI-1 was genotyped by TaqMan PCR. Cox regression analysis adjusted for age, sex and acquired risk factors of VTE showed no evidence of an association between PAI-1 genotype and risk of VTE recurrence in the study population as a whole. However, by including an interaction term in the analysis we showed that FVL but not PTM modified the effect of PAI-1 genotype: patients with the 4G allele plus FVL had a higher risk of VTE recurrence [hazard ratio (HR) =2.3, 95 % confidence interval (CI) =1.5-3.3] compared to patients with the 4G allele but no FVL (reference group) or FVL irrespective of PAI-1 genotype (HR=1.8, 95 % CI=1.3-2.5). Compared to reference group, 5G allele irrespective of FVL was associated with lower risk of VTE recurrence only when compared with 4G allele together with FVL. In conclusion, FVL has a modifying effect on PAI-1 polymorphism in relation to risk of VTE recurrence. The role of PAI-1 polymorphism as a risk factor of recurrent VTE may be FVL dependent.